The invention relates to a method and apparatus for call processing. Packet-based data networks are widely used to link various types of network elements, such as personal computers, servers, gateways, network telephones, and so forth. Data networks may include private networks (such as local area networks or wide area networks) and public networks (such as the Internet). Popular forms of communications between network elements across packet-based data networks include electronic mail, file transfer, web browsing, and other exchanges of digital data.
With the increased capacity and reliability of packet-based data networks, voice communications (including telephone calls, video conferencing, and so forth) over data networks have become possible. Voice communications over data networks are unlike voice communications in a conventional public switched telephone network (PSTN), which provides users with dedicated, end-to-end circuit connections for the duration of each call. Communications over data networks, such as IP (Internet Protocol) networks, are performed using packets or datagrams that are sent in bursts from a source to one or more destination nodes. Voice data sent over a data network typically shares network bandwidth with conventional non-voice data (e.g., data associated with electronic mail, file transfer, web access, and other traffic).
Various standards have been proposed for voice and multimedia communications over data networks. One such standard is the H.323 Recommendation from the International Telecommunications Union (ITU), which describes terminals, equipment, and services for multimedia communications over data networks. Another standard for voice and multimedia communications is the Session Initiation Protocol (SIP), which establishes, maintains, and terminates multimedia sessions over a data network. SIP is part of multimedia data and control architecture developed by the Internet Engineering Task Force (IETF). The IETF multimedia data and control architecture also includes other protocols to enable voice and multimedia sessions over data networks.
To establish a call, an originator device sends a call request to a destination device, with the call request containing an identifier of the destination device. The identifier may be a telephone number, a SIP address, or some other identifier. In a network having multiple network elements capable of participating in a voice or multimedia session, each network element is typically assigned a unique identifier. In a SIP network, one or more SIP proxies may be used to resolve locations of devices associated with a logical identifier. Thus, for example, a call request containing a telephone number may be processed by the SIP proxy, with the telephone number resolved to the physical location of the destination device.
Although improved technology has enhanced the flexibility in how a call session is established, some limitations still exist. For example, in a conventional network, convenient mechanisms have not been provided to enable a group of network elements to be associated with a single or a reduced number of logical identifiers for call sessions over packet-based networks. A need thus exists for a method and apparatus to enable more flexible techniques and mechanisms for call processing over packet-based data networks.